Frank Low, Pioneer of Infrared Astronomy, 1933-2009

Written by Raphael RosenJet Propulsion Laboratory

On June 11th, Dr. Frank Low, one of the people responsible for the
rise of infrared astronomy, died in Tucson. He was 75 years old.

Dr. Low was also intimately involved with the Spitzer Space
Telescope, not only by making discoveries that made the design of
Spitzer possible, but also as the Facility Scientist of the Spitzer
mission.

He began his career in the early 1960's at Texas Instruments, after
having studied physics at Yale and Rice Universities. At T.I., he
invented an extremely sensitive device that measured minute changes in
temperature. This device, made of the element germanium, mixed with
small amounts of gallium, would register changes of temperature by
changing its electrical resistance. (Such a device is called a
"bolometer".) This device, Low realized, could be used to detect
infrared radiation, and thus revolutionized the practice of peering
into space to look for stars and galaxies in infrared wavelengths.

In 1962, Low moved from Texas Instruments to the National Radio
Astronomy Observatory, in Green Bank, West Virginia. There, he tested
his bolometer by pairing it with a radio telescope. Then, in 1965, he
moved to the University of Arizona, where he taught for almost thirty
years. He also founded a company, Infrared Laboratories Inc., which
would later supply parts to NASA missions and to other astronomers
pioneering the field of infrared astronomy.

But Low not only dramatically improved the instruments that
astronomers used to look at stars. He also improved the way in which
they were used.

The Earth's atmosphere is a problem for infrared astronomers. The
water vapor and other gasses absorb infrared radiation, reducing the
amount collected by telescopes on the ground. So, astronomers usually
try to put their scopes in the highest and driest places on the planet,
to reduce not only the amount of gas between their instruments and the
starlight, but also to reduce the amount of water vapor in the air.

Frank Low took this approach one step further, and put infrared
telescopes on airplanes. In 1965 and 1966, he put a 2-inch infrared
telescope on a U.S. Navy Douglas A-3 bomber, and a 12-inch scope on a
NASA Learjet.

This new approach produced immediate results. Using the Learjet
scope, Low discovered that both Jupiter and Saturn â the two largest
gas giant planets in our solar system â were emitting more energy than
they were absorbing from the Sun. Therefore, Low concluded, they both
must have an internal source of heat.

Going further, Dr. Low and others began pressuring NASA to build an
infrared telescope that would be put into space. This new instrument,
the Infrared Astronomy Satellite (IRAS), was launched in 1983, and was
a joint venture of the United States, the United Kingdom and the
Netherlands.

IRAS found more than 500,000 sources of infrared radiation in space,
including interstellar clouds, stars, and galaxies. IRAS also found
dust and debris around other stars, suggesting that the planets might
be forming, or might have formed, around other stars besides our Sun.

Low was then present at the birth of the Spitzer Space Telescope
mission. NASA planned to replace IRAS with another infrared telescope
satellite, originally called the Shuttle Infrared Telescope Facility.
But, the project, later renamed the Spitzer Space Telescope, soon
became too expensive, and was put on hold. Low then had an epiphany
that allowed the project to continue.

Rather than placing the telescope in a heavy, insulating vacuum
vessel that would keep the telescope cool during launch, Low proposed
that the telescope be launched warm and uninsulated, and left to cool
off in the depths of outer space. (Usually, infrared telescopes must be
cooled, so their own infrared radiation does not interfere with their
measurements.) This insight allowed the project to continue, and
initiated a new way of building and launching infrared telescope
satellites, paving the way for the upcoming James Webb Telescope, a
huge 6.5-meter infrared telescope scheduled for launch in 2014.

Erick Young, an astronomer who worked with Frank Low at the
University of Arizona, says that Low had a "major impact" on his career.

"He taught me the importance of instrumentation and detectors to the
field," Young says, "and that's been my direction ever since his
influence."

Young also claims that Low "had a remarkable ability to see 'obvious' things that had been missed by others."

Says Young, "This intuitive ability also carried over to technical
solutions. He had a knack for coming up with elegant solutions to
difficult problems."

Low is survived by his wife, two daughters, a son, a sister, and six grandchildren.

The Spitzer Space Telescope is a NASA mission managed by the Jet Propulsion Laboratory. This website is maintained by the Spitzer Science Center, located at IPAC on the campus of the California Institute of Technology.